


Trust Your Instincts

by ButterfliesAndPenguins



Category: Granblue Fantasy (Video Game)
Genre: Creampie, Draph physicality, Established Relationship, Fingering, It's ok You Are Safe Now My Sweet Child, Listen that's why I wrote this fic and that's probably why you're here, Love Confessions, M/M, Rein's Huge Draph Dick, Rimming, Size Difference
Language: English
Status: Completed
Published: 2020-05-04
Updated: 2020-05-04
Packaged: 2021-03-01 19:40:31
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,529
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23992444
Author URL: https://archiveofourown.org/users/ButterfliesAndPenguins/pseuds/ButterfliesAndPenguins
Summary: Reinhardtzar's draph instincts begin to take over while they are together... and Cain is more than appreciative.
Relationships: Cain/Reinhardtzar (Granblue Fantasy)
Comments: 10
Kudos: 126





	Trust Your Instincts

The floorboards groaned. From a glimpse of the wide beams, Cain managed to guess they had somehow made their way back to Reinhardtzar’s cabin in the Grancypher. He also presumed that the rough texture below his legs meant he was seated on top of the dresser, a large hand hooked behind each of his knees, yanking him forward. Good. They were alone. 

Cain had been feeling a lot of things this week. Too many, in fact. Things that sounded stupid or insincere if you actually said them aloud. He’d been avoiding talking about any of it since their first hurried tryst together a few weeks ago, so this alternative was a relief. Preferable, even.

Cain surged forward and kissed the draph hungrily, banishing any chance for him to back down or pause to think. Their first time together had been too full of that, plagued by hesitation and worry for the other. This time he knew what they were both in for.

From his seat on the dresser, Reinhardtzar could loom just over him, and the draph’s hands pressed downward, wide arms framing Cain on either side as he leaned into his kiss. Cain let his hands slide appreciatively up the arc of his firm shoulders and around the back of his neck. Reinhardtzar hummed, pulling away for a brief moment only to kiss at Cain’s neck, his hot breath misting over his skin.

“Shall we move this to my bed?” he asked, managing a sly charisma Cain hadn’t known he possessed. 

“Race you there,” Cain grinned hazily.

“Hmm, deal,” Reinhardtzar bit playfully, yet firmly down on the tendon at Cain’s neck and he gasped, head falling backward. As soon as he did, the draph scooped him up off the dresser and whisked him to the bed, tossing him down onto the mattress so his whole body bounced lightly. Pausing for a moment, the draph general removed his shirt at the foot of the bed. Cain’s jaw dropped quietly at the casual, yet clearly intentional flex of his generous muscles. Reinhardtzar unlaced his tall boots as well, sliding onto the firm mattress with a soft grunt. Cain blinked out of his stupor and tried to remember to be the one guiding the situation. Reinhardtzar tugged at Cain’s collar tauntingly.  
  
“Care to join me?”

Cain reached a hand out for Reinhardtzar’s chest and slid the palm against his firm skin. “Hmm, why don’t you help me out of these?”

Reinhardtzar raised an eyebrow. “Are you stuck? Aren’t they _your_ clothes?”

“Rein, come on,” Cain hissed, rolling his eyes. He pressed himself close, leaning up to murmur into his ear. “I _want_ you to undress me. ”

“Oh…” Reinhardtzar grumbled.

Cain guided his hands invitingly, and Reinhardtzar slid his rough, thick fingers under Cain’s shirt, sending shivers down his spine. 

When he had fully undressed him, something in the draph’s expression shifted. His tough brow loosened and his eyes focused intently, searching Cain’s face for something. He opened his mouth as if he was about to speak, but hesitated. Cain blinked, looking back up at him, but silence passed between them. He smoothed a palm over Reinhardtzar’s chest, trying to anchor his focus, but the moment flitted away and the draph kissed him, a little haltingly this time. 

Cain smiled against his kiss and tangled his fingers in the draph’s long, coarse hair. “Has the sight of me taken your breath away?” he teased, trying to lighten the mood.

Reinhardtzar nodded. “Yeah…” he said with complete, startling sincerity.

Cain blinked, not at all expecting this. He laughed gently. “How cute…”

“Huh?” he huffed.

“Nothing,” Cain hummed, quickly shifting the focus. “You’re really gorgeous, you know that? I can’t get enough of you…” He stretched upward to kiss at the wide jaw, shifting so their naked torsos were flush. Reinhardtzar’s skin was fiercely hot, it was no wonder he always wore an open shirt. He could feel the heavy heartbeat pounding in his chest. Reinhardtzar breathed shakily. Cain’s kisses drifted upward toward his ear, ending at the root of his horn. The draph’s grip on Cain’s waist tightened pleasantly.

“Sensitive here?” Cain asked coyly, pressing another kiss and brushing his lips against the hard, ridged enamel. His fingers reached to caress the draph’s long, petal-shaped ear, indulging a curiosity Cain had possessed for quite some time. The ear’s shape was firm, but covered in a delightfully soft fuzz. Cain kissed it lightly and the draph’s ear twitched, jingling his long earrings. He couldn’t help but chuckle.

Seeming slightly irked, Reinhardtzar pulled Cain away from his perch and kissed him, cupping his head with one wide hand. Cain adored the way the draph’s huge hands wandered over him. His palms were like well-oiled leather, and his hand could grasp half of Cain’s entire head. Cain couldn’t deny the quiet thrill of knowing firsthand what those fists were capable of crushing, while they held him now with gentle reverence. He wanted them on every inch of his body at once. Cain wound his arms around his partner’s neck, trying to tell him this, deepening the kiss. 

Reinhardtzar’s mouth, too, enveloped his. The draph was a bit ungraceful at kissing, his teeth sometimes joined the mix, but Cain gently attempted to guide him, teaching him to hang on for longer, and parting his own lips wider in invitation when the moment was right. Between kisses his voice stirred, rumbling as he caught his breath. The deepness of his quiet growl made Cain’s head spin. He hooked one leg around Reinhardtzar’s waist, squeezing and rocking his hips gently for contact, and felt the draph gasp through his nose. 

“Rein,” he whispered against his lips, dragging a hand downward over the buttons at his pants. “Let’s get these off. I want to see _all_ of you.”

The draph shivered, obliging and pulled back to shift out of the last of his clothes. Reinhardtzar tried to resume their kissing, but after a moment Cain stopped him.

“Wait,” he said quietly. Sliding his fingers along the leather straps along his brow and cheek, Cain loosened Reinhardtzar’s eyepatch and removed it carefully, exposing the scarred socket. He caressed the skin on his brow, which felt softer where it was typically covered, and kissed his face.

Cain gazed up at him fondly, his affection welling up in his chest. “There, now I can see all of you.”

Reinhardtzar’s brows pinched together oddly. He seemed enraptured when Cain’s attention was completely on him, fully acknowledging him. For a moment, Cain felt he could ask anything and the draph would do it without even thinking. He smiled, rising up to kiss him deeply again.

Reinhardtzar reciprocated for a moment, then broke apart suddenly. He inhaled, pressing their foreheads together, and then the words that seemed stuck before tumbled forth.

“...I love you.”

Cain froze, his eyes wide. It felt like a crystal had formed in his throat, painfully sharp. He hadn’t expected to hear those words, but he definitely hadn’t expected they could seize him so strongly by the heart.

Reinhardtzar tensed, immediately looking uncomfortable. “I didn’t mean to… uh, bad timing. I didn’t wanna kill the mood— It just slipped out—”

“Shh, stop, come here,” Cain placed both hands on the draph’s cheeks, pulling him close and kissing him fiercely, certain Reinhardtzar could taste the sting of emotion in his throat. Reinhardtzar halted, but softened at the sincerity in Cain’s lips, finally accepting them.

Cain breathed unsteadily, thinking of all that they had been through together and how it couldn’t possibly be summarized in so few words. But he echoed them anyway. “I love you, too.”

“Heh,” Reinhardtzar gave a single, breathless laugh, clearly from relief. “Good…” he concluded unpoetically. 

Cain grinned and kissed him again before he could protest. He let his mouth wander downward, lingering over Reinhardtzar’s chest and taking in the broad muscle there. Reinhardtzar grunted as Cain’s lips closed over one of his dark nipples. Cain’s glance flicked upward playfully. 

Eager to speed things along, Cain reached his hand down to grasp Reinhardtzar’s cock. Cain bit his lip with a jitter of excitement. It was heavy, nearly the width of his own forearm, and his fingers couldn’t encircle the distance. He stroked it slowly, appreciating the thick, smooth foreskin before joining a second hand.

Reinhardtzar grunted nervously. He was only half-hard, but Cain could feel him swelling quickly in his hands. He smirked to himself, letting his fingers drift further downward to sweep underneath his balls. They were intimidatingly large, and covered in a soft fuzz like his ears. Cain lingered there for a moment before returning to stroking his length with two hands. The draph was watching him, transfixed, the grip on his shoulder tightening with each stroke.

“Rein,” Cain said enticingly, keeping his voice airy. “I want you… The thought of you inside me is driving me crazy…” 

Reinhardtzar grunted helplessly, his breathing growing more ragged and desperate. 

Cain felt his own cock stiffening eagerly as he worked. Feeling bold, he squeezed, pulling back the foreskin as the draph’s hips jumped.

Suddenly a forceful hand was on his wrist, wrenching him away. When he looked up, Reinhardtzar was panting, staring into his eyes warningly. 

“Wait,” he commanded, voice unsteady. “Not yet.”

Cain blinked up at him innocently, hoping to provoke him into whatever Reinhardtzar was ready for next. The draph nodded toward a drawer by his bed. Cain leaned over and opened it, searching until he spied a grey glass jar, handing it to him.

“This…” he mumbled, “This will help. Draphs use it… it’s... enchanted.”  
  
Cain’s eyes widened with anticipation. He spied enough of the writing on the label to guess that the lubricant helped relax muscles for… size difficulties. Female draphs were typically even smaller than he was, after all.

“Er… first…” Reinhardtzar’s eyes were darting about, finally managing to meet his gaze.

Cain pressed a reassuring palm to his cheek. “What do you want?” he asked invitingly.

Reinhardtzar drew a heavy breath. “Turn around,” he said, struggling to keep his voice gentle.

Cain smiled, quite enjoying how flustered his usually unshakable partner was. He obliged, shifting on the bed until his back was turned. He suddenly felt exposed, facing away from the radiating heat of the draph, and turned his chin to glance behind him.

Behind him, Reinhardtzar’s eyes were heavily lidded with desire, staring down at him in almost a trance-like gaze. Cain wondered what the sudden shift meant, when the draph leaned forward, resting his forehead onto Cain’s back, simply breathing him in for a moment. His wide hands found Cain’s hips, pulling him slightly closer, seemingly to steady himself. The draph brushed his lips as he moved downward, and Cain realized he was almost nuzzling against his skin. He froze for a moment. Was this some sort of compulsory draph instinct?

Cain was about to teasingly ask this, when Reinhardtzar shifted his hands along Cain’s ribs, easily bending him forward, and in the same movement dipped his face downward, closing his mouth over the rim of Cain’s entrance. Cain gasped, feeling the wind instantly knocked out of him at the sensation. Reinhardtzar did not seem to notice, kissing deeply and slowly running his broad tongue over Cain’s hole. 

Cain gripped the sheets in his fist, quickly trying to brace himself against the flood of unexpected sensation. It was overwhelming, he had to fight the instinct to lurch away as his cock twitched, swelling at the stimulation. He willed himself to relax against Reinhardtzar’s mouth, leaning back into the sensation, even as it was threatening to carry him too far too quickly. 

Reinhardtzar’s breath growled lightly, vibrating against his skin, and Cain shuddered. He realized he should let his voice loose, knowing how well Reinhardtzar responded to encouragement. He moaned reverently, letting the hitch of his breath carry loudly. The draph hummed gladly in response, echoing him.

One of Reinhardtzar’s hands moved to grip the side of Cain’s ass, digging a thumb in to pull him further open, allowing his tongue to finally slide inside of him. Cain cried out, biting down on his voice in slight embarrassment. The draph’s tongue was _large_ , filling him with wet heat and sending sparks straight to his vision. Cain felt his cock begin leaking helplessly onto the sheets. 

The draph dipped his tongue deeper, devouring him steadily, painting him with saliva. Cain shivered, he didn’t dare disturb the draph in his trance-like state. Even if things ended abruptly for him, right here, it would be worth it.

He let his voice whine desperately. There was something overpowering about the touch of his tongue, more than the friction of any fingers or skin inside him, that reduced him to trembling and made his voice undignified.

Finally Reinhardtzar surfaced with a light smack of his lips, raising his head. He leaned forward, letting his hot breath pour over Cain’s skin, and once again rested his cheek on Cain’s back, breathing heavily with want. His chin was slick and warm, making Cain wince with a smile. His hips shifted closer, clearly eager.

Cain fumbled, reaching limply for the jar Reinhardtzar had requested earlier and handing it to him. 

“Here…”

Breath rumbling, Reinhardtzar took it from him shakily, dipping inside and swiftly smearing some over Cain’s wet entrance, before sliding one thick finger inside.

Cain hissed in surprise, jumping slightly.

“S—Sorry…” Reinhardtzar growled. “Shoulda warned—”

“Just move—” Cain gasped, shaking his head. “It’s fine…”

The magic of the paste was already taking effect. Cain felt himself being stretched easily, tingling warmly as Reinhardtzar easily slid another impressively large finger inside him, twisting and pulling gently. Reinhardtzar was lingering too long, fingers digging and hooking deliciously. It was pushing Cain too close to the edge.

“Slow down—” Cain gasped. “I’m gonna—”

Reinhardtzar grunted, trying to find a gentler pace, but clearly too worked up and desperate himself. Cain felt the pressure building, swelling out of reach in his yet untouched cock. Reinhardtzar tried to pull his fingers out gently, but it was too late. Cain held his breath, trying to stop the rush of pressure, but only half-succeeded. His cock throbbed weakly, twitching achingly in a ruined half-orgasm, still oozing wetly. He groaned helplessly. This was too much for him to pace himself, he wasn’t sure how long he could last.

Slick sounds behind him warned him that Reinhardtzar was preparing, unable to slow down. 

“Hurry,” Cain complained.

Reinhardtzar grunted in acknowledgement, lining his hips up and spreading him with both hands. Cain had just enough time to gasp for breath before Reinhardtzar slid inside him. He felt a moment of panic, fearing the draph might not fit, before realizing his fear was too late, it was already deep inside him, and the enchanted lubricant had done its job beautifully. The burning sensation of fullness was masked by a pleasant buzz of heat. Cain sighed appreciatively.

“You ok?” Reinhardtzar managed to ask shakily, barely holding his movement back.

“Mmhmm,” Cain nodded enthusiastically. “Ahh— please, just move!”

Reinhardtzar needed no further encouragement, his fingers gripped Cain’s hips like a vice as he pulled him, thrusting slowly at first, then gaining momentum.

Cain’s breath tumbled out of him in rhythm with each thrust. He let the movement take over him, sinking back onto Reinhardtzar’s cock eagerly. The intense fullness required his focus to stay relaxed, resetting the pressure that had been mounting behind his orgasm and mercifully slowing his desperation. His confidence was rising, he knew he could take whatever the draph had to give.

“More… Rein you feel—ah!—amazing…” he crooned. “So good… More…!”

Reinhardtzar’s breath hitched as he complied, clearly being driven closer to the edge by Cain’s response to him. 

They continued, Cain bracing himself at the mercy of the draph and relishing every moment. He could hear Reinhardtzar’s remaining composure slipping, feeling his rhythm getting slightly uneven. The depth plunging into him again and again was fierce, but the addicting sense Cain could not stop chasing was the magnificent thickness stretching him so deliciously wide. He gave himself over to it.

The pressure was beginning to feel just slightly raw, things were becoming oversensitive just as Reinhardtzar leaned in closer, grunting heavily. He gasped into Cain’s ear.

“Close… you alright…?”

Cain nodded breathlessly. “Don’t stop, _please_. Finish inside me.”

Reinhardtzar swore quietly at Cain’s seductive voice. “Brace yourself… Hold on,” he growled.

Cain glanced over his shoulder into his eyes, then reached up and gripped one of Reinhardtzar’s horns to steady himself as instructed. The draph moaned, sighing with affection, clearly overwhelmed by the unexpected gesture. He gently grasped Cain’s hand, pulling it off of his horn and pressing it back into the sheets, covering it protectively with his own. Cain moaned through pressed lips as he sought enough hold while Reinhardtzar gripped his torso firmly in the other hand, cradling him harshly.

With a fierce growl that vibrated against Cain’s back, Reinhardtzar thrust into him roughly, hips shuddering. Cain could feel the pulse as he came heavily, thrusting erratically while he rode out his orgasm inside him. Cain’s own cock was twitching, desperate for sensation, but his hands were trapped beneath the draph’s. He moaned, twisting to reach for something to give him release as Reinhardtzar clearly struggled to regain control of himself. As soon as he could move, still pulsing inside of him, the draph reached a massive hand below Cain’s stomach and closed around his length, stroking weakly. Cain bucked into his hand and almost instantly felt himself come, aching with the final release.

Reinhardtzar’s touched buzzed against his cock as it was coated in its own warmth, dissolving into slickness. Cain was floating, unsure if the weightlessness was from blissful overstimulation or if Reinhardtzar was truly holding him up in his fierce grip. The draph slid back and forth inside him a few more times with dizzying slowness, savoring the last of their friction. His orgasm had outlasted Cain’s by at least a full minute, the man was gaining a newfound awe for draph physicality.

Reinhardtzar was breathing shakily, his grip on Cain’s waist beginning to falter. As he let go, Cain could feel the indentations left behind on his skin and smiled with satisfaction. 

“I’m—I’m gonna pull out now,” Reinhardtzar panted awkwardly. Cain slumped forward weakly, nodding into the twisted, damp sheets. When the draph pulled away, his cock slipped downward heavily, and Cain sighed appreciatively. He could feel his entrance dripping liberally in its wake. 

“Rein, that felt… so good…” He grinned. “You’re incredible…”

The draph managed to laugh weakly, sighing as he sat down shakily. “You… you too.”

Cain rolled onto his side and winced, feeling the discomfort of so much fluid inside of him with a twinge, and knew he would have to clean up very soon before things got worse. Settling for a towel near the bed in the meantime, he turned to see Reinhardtzar collapsed on his back, catching his breath and looking helplessly exhausted. He seemed drowsy and unfocused, such a stark change from moments ago that Cain scooted to lie beside him, peering into his face with concern. He poked his shoulder gently.

“Everything ok? Is this normal for you?” He asked quietly.

Reinhardtzar nodded vaguely. “I think so…”

Cain smiled with bewilderment at his uncertainty. Was it the emotion of this time together, or was Reinhardtzar a bit inexperienced with this? Whatever the reason, staring down at his exhausted frame, Cain felt instantly protective of him. Perhaps his body was responding somehow in kind to the draph’s physical state, or perhaps he simply loved this man. For the moment he ignored his own discomfort, brushing back Reinhardtzar’s thick hair and gently kissing him.

“You were fantastic, Rein,” Cain praised him, his own body still tingling with afterglow. Reinhardtzar looked up wearily, seeming proud but a little surprised.

The draph reached for Cain’s arm and tried to pull him close, but his grip was comically weak and his hand slipped. Cain laughed fondly and settled against him closely.

Reinhardtzar inhaled slowly, mumbling in Cain’s ear. “Draphs can be... very defenseless and weak after mating… so we only mate with someone we deeply trust.” He brushed a thumb over Cain’s ear.

Cain blinked, his heart swelling with both affection and embarassment. 

“Well now,” Cain teased, catching the draph’s hand in his. “Who knew the great Tzar had such a gentle side?”

Reinhardtzar pulled a face, swatting his hand away in retaliation.

Cain laughed. “Just kidding. Of course we share so much trust. We’re partners, after all, you and I.”

The draph smiled again, shaking his head lightly. His eyelids began to sink lower, and his breathing slowed, heavy and loud. He reached out his broad, shaky hand again, resting it on Cain’s cheek. Cain pressed his own smaller hand against it fondly. He pressed it close and whispered against his palm.

“I love you, Reinhardtzar.”

The draph smiled slightly, eyes closed. “‘S good. I’m glad… that…” He trailed off, drifting to sleep mid-sentence. 

Cain laughed and kissed his palm, pulling the draph’s hand down and cradling it against his chest and whispering, “Me too.”

**Author's Note:**

> There is somehow not enough love for these two out there, so in honor of Rein's SSR finally coming out I offer this. Hope you enjoyed, thanks for reading!


End file.
